The second and third books above were released at the height of the 1990s speculator boom. One's worth $20USD on a good day. The other you can find in dollar bins. The first? Well, that one's now on sale (although I have, ahem, doctored it a little). On eBay a first printing, unsigned and still in the polybag, has reached a price of $20.50. Soon to plummet as, you guessed it, the member of the FF who died in the issue eventually returns.
I'm not getting into how major characters in comics really . That argument's been done to death. If the public at large is gullible enough to believe DC would really kill Superman, or Marvel would really kill Captain America, well...like I said, so not going there. This is about the polybag.
They're comics. Read 'em. If you like 'em, recommend them to friends. Lend your books out. Donate them to your local library, or ask to put some at your local pediatrician's office waiting room for the kids there. Don't try to hoard 'em hoping one day they'll help you put your kids through college. Supply and demand, folks.
There are better ways to popularize the product than emphasizing death. Can we please find them? Soon?